1. Field of the Invention
The present invention relates to fiber coating and, more particularly, to a shape memory polymer coating for hair and other fibers.
2. Description of the Related Art
Polymeric coatings have been used in a wide range of application fields such as automobiles, beauty products, and medical devices. Among the existing hair styling products (gels, sprays, etc) and fabric coatings (e.g., starch), a big disadvantage is that they do not enable reversible styling, or “re-styling”, with two styles in memory. Thus, a need exits for the styling products with good shape memory properties and good hair or fabric binding ability.
Shape memory materials are those materials that have the ability to “memorize” a macroscopic (permanent) shape, be manipulated and “fixed” to a temporary and dormant shape under specific conditions of temperature and stress, and then later recover to the original, stress-free, condition under thermal, electrical, or environmental command. This recovery is associated with elastic deformation stored during prior manipulation. Shape memory materials have aroused great attention by scientists and engineers due to their capacity to remember two shapes at different conditions. This gives materials great potential for sensors, actuators, smart devices of great potential for applications that range from consumer products to sporting goods and medical devices. The most prominent and widely used shape memory materials currently are shape memory alloys (SMAs). Their shape memory effect comes from the existence of two stable crystal structures: the high temperature-favored austenitic phase and low temperature-favored (and “yield-able”) martensitic phase. Downsides that limit their application exist, including limited recoverable strains less than 8%, inherently high stiffness, high cost, comparatively inflexible transition temperature, and demanding processing and training conditions. Such limitations have provided motivation for the development of alternative materials, especially shape memory properties, the good binding abilities, and the intrinsic nature (non-tacky, odorless, etc) make these materials good candidates for applications as coatings on flexible substrates, such as hair, fabric, paper, sails, plastic film, among others.